EP0330662B1 - Lichtabnehmer für ein photostimulierbares phosphorbilderfassungsgerät - Google Patents

Lichtabnehmer für ein photostimulierbares phosphorbilderfassungsgerät Download PDF

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Publication number
EP0330662B1
EP0330662B1 EP87907063A EP87907063A EP0330662B1 EP 0330662 B1 EP0330662 B1 EP 0330662B1 EP 87907063 A EP87907063 A EP 87907063A EP 87907063 A EP87907063 A EP 87907063A EP 0330662 B1 EP0330662 B1 EP 0330662B1
Authority
EP
European Patent Office
Prior art keywords
light
light collector
photo
open end
mirror
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87907063A
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English (en)
French (fr)
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EP0330662A1 (de
Inventor
Yali Ellen Chan
John C. Boutet
Robert Walter Kulpinski
Anthony Richard Lubinski
James Frederick Owen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0330662A1 publication Critical patent/EP0330662A1/de
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Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/0281—Details of scanning heads ; Means for illuminating the original for picture information pick-up with means for collecting light from a line or an area of the original and for guiding it to only one or a relatively low number of picture element detectors

Definitions

  • the invention relates to apparatus for reading out the image stored in a photo-stimulable phosphor image recording medium, and more particularly to apparatus for collecting and detecting the radiation emitted from the photo-stimulable phosphor in response to interrogation by stimulating radiation.
  • a photo-stimulable phosphor sheet is exposed to an imagewise pattern of short wavelength radiation, such as x-radiation, to record a latent image pattern in the photo-stimulable phosphor sheet.
  • the latent image is read out by stimulating the phosphor with a relatively long wavelength stimulating radiation such as red or infrared light.
  • the photo-stimulable phosphor releases emitted radiation of an intermediate wavelength such as blue or violet light in proportion to the quantity of short wavelength radiation that was received.
  • the photo-stimulable phosphor sheet is scanned in a raster pattern by a beam of light produced for example by a laser deflected by an oscillating or rotating scanning mirror and the emitted radiation is sensed by a photodetector such as a photomultiplier tube to produce the electronic image signal.
  • a photodetector such as a photomultiplier tube
  • the photo-stimulable phosphor sheet is placed on a translation stage and is translated in a page scan direction past a laser beam that is repeatedly deflected in a line scan direction to form the scanning raster.
  • the light collector proposed by Tanaka et al comprises a sheet of light transmitting material that is flat on one end, and rolled into an annular shape on the opposite end. The flat end of the light collector is positioned adjacent the scan line on the photo-stimulable phosphor sheet. The light receiving face of a photomultiplier tube is placed against the annular end of the light collector.
  • Light emitted from the phosphor sheet enters the flat end of the light collector and is light piped to the photomultiplier tube. Improved light collection efficiencies are achieved by having two such light collectors, one on each side of the scan line, or by placing a long narrow reflector opposite the flat end of the light collector to increase the collection window of the light collector.
  • the transparent light collector has the drawback that it is inherently complicated to manufacture. Furthermore, the collection efficiency of transparent light guides is limited due to their absorption in the wavelength range of light emitted by the photo-stimulable phosphor sheet (e.g. blue-violet).
  • EP-A-0 144 089 discloses a light collector that is a rectangular slab of transparent material with a row of photomultiplier tubes along one edge. Although this would be easier to manufacture them the light collector of US-A-4 346 295, it still suffers from the problem of light absorption noted above.
  • Such reflection of the stimulatlng radiation onto the photo-stimulable phosphor may occur from the light collecting edge of the light guide described above.
  • Examples of the image degradation caused by prestimulation include a reduction in the contrast of images due to flare induced emission from high exposure areas. This adds unwanted signal to low exposure areas. Shadow artifacts are produced in the image when a high exposure object on a low exposure background field is scanned. The signal-to-noise ratio in all image areas is degraded. Laser noise is enhanced since a large area of the phosphor is exposed to a low level of stimulating radiation, the light emitted from this area will follow the fluctuations in laser power, thereby amplifying the effect of the laser noise.
  • This light collector has a generally rectangular mirror box with relatively wide plane mirrors on the top and bottom, relatively narrower mirrors on two opposite sides, and two opposite open ends. One of the open ends is arranged adjacent the scan line of the photo-stimulable phosphor sheet, and a plurality of photomultiplier tubes are arranged at the other open end of the mirror box. An elongated reflector is arranged opposite the one open end of the mirror box for directing light emitted from the phosphor into the open end of the mirror box.
  • the faces of the photomultiplier tubes are arranged at an oblique angle with respect to the end of the mirror box, and the unision box is tapered so that the end near the photomultiplier tubes is wider than the end near the photostimulable phosphor sheet.
  • the light collector includes a generally rectangular mirror box 10, having relatively wide top and bottom mirrors 12 and 14, and relatively narrow side mirrors 16 and 18. At one end of the mirror box are a row of photomultiplier tubes 20.
  • the photomultiplier tubes 20 are provided with rectangular light receiving faces so that they can be efficiently stacked along the end of the mirror box.
  • the open end of the mirror box opposite the photomultiplier tubes extends along the scan line 24 of a laser beam 26 that is deflected in the direction of arrow A to scan the photo-stimulable phosphor sheet 28.
  • An elongated reflector 30 is positioned opposite the open end of the mirror box 10 to reflect emitted light into the mirror box.
  • Fig. 2 is a cross-sectional view of the light collector shown in Fig. 1.
  • some of the stimulating radiation from scanning beam 26, as indicated by rays 32 is reflected from the surface of the phosphor sheet 28 and enters the mirror box 10.
  • Most of the stimulating radiation is absorbed by the filter 22, but some is reflected as indicated by phantom rays 34 back onto the surface of the photo-stimulable phosphor. These rays reflected off the surface of the filter 22 can be a cause of prestimulation in this light collector.
  • the faces of the photomultlplier tube are arranged at an oblique angle with respect to the end of the mirror box as shown in Fig. 3.
  • the rays 32 which directly reach the face of the infrared filter 22 are subject to multiple reflections (as shown by phantoms rays 34 in Fig. 3) on the return trip. Due to the multiple reflections, most of the energy in the rays is dissipated by the time they reach the phosphor sheet.
  • the top and bottom mirrors 12 and 14 are angled with respect to each other so that the end of the mirror box near the photomultiplier tubes is wider than the end near the photo-stimulable phosphor sheet as shown in Fig. 4.
  • the side mirrors 16 and 18 may be angled with respect to each other with their wide ends near the photodetectors, to further increase collection efficiency and reduce prestimulation.
  • Fig. 5 is a top view of a light collector having angled side mirrors. As a result, a greater percentage of the emitted light reaches the photomultiplier tube with fewer reflections, and stimulating light that reaches the infrared filter 22 directly (as shown by rays 32 in Fig. 4) and is reflected from the surface of the infrared filter (as shown by phantom rays 34 in Fig. 4) is trapped.
  • Prestimulation may be further reduced by providing a mask 36 as shown in Fig. 4 extending between the bottom edge of mirror 30 and the bottom mirror 14 of the mirror box.
  • the mask 36 defines a slot 38 through which the scanning beam passes to the surface of the photo-stimulable phosphor 28, and which allows the emitted light to enter the collector.
  • Prestimulation may be further reduced by applying an antireflection coating to the surface of filter 22.
  • a light collector according to the present invention was constructed using diamond machined aluminum plates for the mirrors.
  • the diamond machined mirror surfaces were 90% reflective for the emitted wavelength of 400 nm.
  • the mirror box was 43 cm wide by 10 cm long.
  • the height of the mirror box at the small end was 2.29 cm, and the height at the large end was adjustable.
  • Five 4 x 8.8 cm rectangular faced photomultiplier tubes were mounted at the wide end of the mirror box with their faces perpendicular to the plane of the phosphor sheet and at an angle of 56° to the top adjustable mirror.
  • An elliptical cross section reflector 30 was employed, having one focal point at the scan line and the other near the detector face. It is noted that the shape of reflector 30 is not critical and, other shapes such as circular cross sections could be employed.
  • the light collector was used in a photo-stimulable phosphor imaging apparatus, and found to have high collection efficiency, low prestimulation and response that was readily made uniform across a scan line by adjusting the individual gains of the photomultiplier tubes.
  • the mirrors were made of metal, optical glass plates with reflective coatings may also be used.
  • the light collector according to the present invention is useful in photo-stimulable phosphor imaging apparatus used for example in x-radiography.
  • the light collector has the advantages that it is easily constructed, has high light collection efficiency, low prestimulation, and uniform collection efficiency across a scan line.

Claims (10)

1. Kollektor zum Sammeln und Nachweisen von Licht, das von einem zeilenweise abgetasteten lichtanregbaren Lumineszenzblatt in einem Lichtanregung verwendenden bildgebenden Gerät abgegeben wird, wobei der Kollekor einen länglichen Spiegel umfaßt, der das von dem Lumineszenzblatt abgegebene Licht zum Kollektor lenkt, dadurch gekennzeichnet, daß
   ein vierseitiger Spiegelkasten (10) zwei größere, einander gegenüberliegende plane, rechteckige Spiegel (12, 14) sowie zwei kleinere, einander gegenüberliegende plane, rechteckige Spiegel (16, 18) umfaßt und daß diese Spiegel so angeordnet sind, daß sie einen Lichtleiter mit zwei einander gegenüberliegenden länglichen offenen Enden bilden, von denen das erste offene Ende zur Abtastzeile (24) auf dem lichtanregbaren Lumineszenzblatt (28) benachbart angeordnet ist;
   eine Mehrzahl von SEV-Röhren (20) am anderen offenen Ende des Spielgelkastens (10) vorgesehen ist und
   der längliche Spiegel (30) zum ersten offenen Ende des Spiegelkastens (10) so benachbart angeordnet ist, daß er das von dem Lumineszenzblatt abgegebene Licht zum ersten offenen Ende des Spielgelkastens lenkt.
2. Kollektor nach Anspruch 1, dadurch gekennzeichnet, daß der längliche Spielgel (30) einen elliptischen Querschnitt hat, daß ein Brennpunkt der Ellipse mit der Abtastzeile (24) zusammenfällt und und der andere Brennpunkt in der Nähe der Lichtempfangsflächen der SEV-Röhren (20) liegt.
3. Kollektor nach Anspruch 1, dadurch gekennzeichnet, daß die größeren planen Spiegel (12, 14) am anderen offenen Ende neben den SEV-Röhren (20) weiter auseinanderliegen als am ersten offenen Ende neben der Abtastzeile (24).
4. Kollektor nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die kleineren planen Spiegel (16, 18) am anderen offenen Ende neben den SEV-Röhren (20) weiter auseinanderliegen als am ersten offenen Ende neben der Abtastzeile (24).
5. Kollektor nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Flächen der SEV-Röhren (20) in einem schiefen Winkel am Ende des Spiegelkastens (10) angeordnet sind.
6. Kollektor nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß eine Maske (36) sich vom Rand eines der großen ebenen Spiegel (14) des Lichtkastens bis an einen Rand des länglichen Spiegels (30) erstreckt und daß die Maske (36) einen Schlitz (38) bildet, durch den ein Abtaststrahl (26) auf das lichtanregbare Lumineszenzblatt (28) gelenkt wird und abgegebenes Licht in den Kollektor einfallen kann.
7. Kollektor nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß es sich bei den Spiegeln um diamantbearbeitete Aluminiumplatten handelt.
8. Kollektor nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß es sich bei den Spiegeln um beschichtete Glasplatten handelt.
9. Kollektor nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß ein Filter (22) vorgesehen ist, das anregende Wellenlängen des Lichts absorbiert und das vom Lumineszenzblatt (28) abgegebene Licht zwischen dem anderen Ende des Spiegelkastens (10) und den SEV-Röhren (20) hindurchlenkt.
10. Kollektor nach Anspruch 9, dadurch gekennzeichnet, daß das Filter (22) eine Antireflexschicht besitzt.
EP87907063A 1986-10-14 1987-10-05 Lichtabnehmer für ein photostimulierbares phosphorbilderfassungsgerät Expired - Lifetime EP0330662B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US917935 1986-10-14
US06/917,935 US4743758A (en) 1986-10-14 1986-10-14 Light collector for photo-stimulable phosphor imaging apparatus

Publications (2)

Publication Number Publication Date
EP0330662A1 EP0330662A1 (de) 1989-09-06
EP0330662B1 true EP0330662B1 (de) 1992-04-08

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP87907063A Expired - Lifetime EP0330662B1 (de) 1986-10-14 1987-10-05 Lichtabnehmer für ein photostimulierbares phosphorbilderfassungsgerät

Country Status (5)

Country Link
US (1) US4743758A (de)
EP (1) EP0330662B1 (de)
JP (1) JPH02500232A (de)
DE (1) DE3778164D1 (de)
WO (1) WO1988002969A1 (de)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4827129A (en) * 1987-02-17 1989-05-02 Siemens Aktiengesellschaft Sweep device for a storage luminescent screen
US5105451A (en) * 1988-12-07 1992-04-14 Eastman Kodak Company Electrographic process utilizing fluorescent toner and filtered detector for generating an electrical image signal
US5105079A (en) * 1990-12-21 1992-04-14 Eastman Kodak Company Split V-roof mirror collector having improved collection efficiency
US5151592A (en) * 1990-12-21 1992-09-29 Eastman Kodak Company Flare minimization in split v-roof mirror collector
FI90922C (fi) * 1991-04-17 1994-04-11 Orion Yhtymae Oy Stimuloidun säteilykuvan valonkeräys- ja luentalaite
DE4115725A1 (de) * 1991-05-14 1992-11-19 Siemens Ag Auslesevorrichtung fuer einen speicherleuchtschirm
US5125013A (en) * 1991-08-08 1992-06-23 Eastman Kodak Company Method of scanning of toned image in a liquid gate
US5140160A (en) * 1991-11-22 1992-08-18 Eastman Kodak Company Collector for storage phosphor imaging system
US5134290A (en) * 1991-11-22 1992-07-28 Eastman Kodak Company Collector for storage phosphor imaging system
JPH0678908A (ja) * 1992-09-03 1994-03-22 Fujitsu Ltd 放射線画像読取装置
US5493128A (en) 1994-08-25 1996-02-20 Eastman Kodak Company Method and apparatus for indexing cassettes
US5506417A (en) * 1994-11-21 1996-04-09 Eastman Kodak Company Light collector for photostimulable phosphor imaging systems
US5541421A (en) * 1994-11-21 1996-07-30 Eastman Kodak Company Light collector having optically coated acrylic substrate
DE19745012A1 (de) 1997-10-11 1999-04-15 Eastman Kodak Co Transportvorrichtung für Röntgenkassetten mit je einem für Röntgenstrahlen anregbaren Leuchtstoffblatt in einem Kassettenbearbeitungsgerät
DE19745011A1 (de) 1997-10-11 1999-04-15 Eastman Kodak Co Vorrichtung zur vereinfachten vertikalen Einführung einer Röntgenkassette in eine Transportaufnahme eines Bearbeitungsgeräts für Röntgenkassetten
US20040159804A1 (en) * 2003-02-13 2004-08-19 Boutet John C. Prism use for CR collector efficiency boost
US7167245B2 (en) * 2004-05-11 2007-01-23 Eastman Kodak Company Alignment of light collector to laser scanline

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JPS60111634A (ja) * 1983-11-19 1985-06-18 富士写真フイルム株式会社 放射線画像情報読取装置
JPS60119166A (ja) * 1983-12-01 1985-06-26 Fuji Photo Film Co Ltd 光検出装置
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Title
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Also Published As

Publication number Publication date
JPH02500232A (ja) 1990-01-25
DE3778164D1 (de) 1992-05-14
EP0330662A1 (de) 1989-09-06
US4743758A (en) 1988-05-10
WO1988002969A1 (en) 1988-04-21

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